The porous media was divided into the fractal aggregation and the non fractal solid phase and pore phase, and a simplified cell model was made to show the microstructure. Porosity, areal fractal dimension, tortuosity fractal dimension, tortuosity, solid phase area and pore phase area of incomplete fractal porous were exhibited. The effective thermal conductivity was built combined with thermal energy and Fouriers law of heat conduction during drying, thermal energy including the heat which required for solid phase during the drying and the heat coming from the circulating hot air. The model was not based on empirical formulas and assumed thermal resistance, and each symbol had definite physical meaning. The result showed that effective thermal conductivity had a negative correlation with the tortuosity fractal dimension, porosity, areal fractal dimension and hot air temperature, while it has a positive correlation with the hot air rate and time.